TUESDAY, Dec. 27, 2016 (HealthDay News) -- Hospitalized patients have a higher risk of cardiac arrest and transfers to intensive care if they're in wards when other patients have recently suffered similar emergencies, a new study suggests.

"This should serve as a wake-up call for hospital-based physicians," study author Dr. Matthew Churpek, an assistant professor of medicine at the University of Chicago, said in a university news release.

"After caring for a patient who becomes critically ill on the hospital wards, we should routinely check to see how the other patients on the unit are doing," he said.

"Following these high-intensity events, our to-do list should include a thorough assessment of the other patients on the unit, to make sure none of them are at risk of slipping through the cracks," he added.

Churpek's team tracked outcomes for adult patients who were admitted to the University of Chicago Medicine from 2009 to 2013. The researchers focused on 13 wards of about 20 beds each, and looked for what happened in the six hours after one patient on the ward experienced a "critical event" -- such as cardiac arrest, death or transfer to an intensive care unit (ICU).

The likelihood of cardiac arrest or an ICU transfer for another patient was greater when one critical event occurred in the six previous hours or more than one event occurred, compared with no critical events, the findings showed.

After one patient on a ward experienced a medical crisis, the odds that a second patient might also do so within the next six hours rose by about 18 percent, the study found. Two such events within a six-hour time period bumped up the odds for a crisis in a third patient by 53 percent, the researchers said. These risks tended to be higher if the events occurred at night versus the daytime.

Study co-author Dr. Samuel Volchenboum said, "We suspected this phenomenon based on our own anecdotal experience. But until we had access to a large, well-curated research-data warehouse, we couldn't perform a study like this." Volchenboum directs the university's Center for Research Informatics.

The study authors stressed that these types of emergency events are relatively rare on most hospital wards. Even though the study included about 84,000 patients over the four-year span, only about 5 percent were transferred to an ICU or experienced in-hospital cardiac arrest, according to the report.

Patients who suffered such events tended to be older and male, and had been in the hospital for an average of nearly two weeks prior to the event. That's four times longer than people who didn't experience these crises, the researchers noted.

The study was funded by the U.S. National Heart, Lung, and Blood Institute and was published Dec. 27 in the Journal of the American Medical Association.